• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2004년도 춘계학술발표회 논문집
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• pp.59-59
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• 2004

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2005년도 춘계 학술발표회 논문집
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• pp.82-85
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• 2005

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 1999년도 춘계 공동학술발표회
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• pp.148-149
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• 1999

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2004년도 춘계임시총회 및 제23회 학술대회
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• pp.40-44
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• 2004

• 한국지구과학회지
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• 제39권4호
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• pp.349-360
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• 2018

This study analyzed variations of learning stress by comparing the salivary cortisol levels of students who participated in Earth Science inquiry activities. The cortisol concentrations between the pre- and post-inquiries of the sample of 34 university students, who had taken the course of 'Basic Earth Science and Experiments', were analyzed. The Earth Science inquiries consisted of geology and astronomy activities. The observational geology activities consisted of a session of 'structure contours and map patterns' and the cognitive astronomy activities consisted of a session of 'representations of horizontal and equatorial coordinates'. These Earth Science inquiry activities were found to cause students to have anxiety, and the thought processes that these activities involved were found to cause learning stress. The variations in cortisol concentrations of students increased by $1.6{\pm}5.9ng\;mL^{-1}$ after conducting observational activities in geology compared with $2.1{\pm}6.2ng\;mL^{-1}$ after doing cognitive activities in astronomy. The analysis of the observational activities in the geology inquiry activities indicated that they were consistent with low levels of learning stress. Conversely, the analysis of the cognitive activities in the astronomy inquiry activities showed significant individual variations in cortisol concentrations. Furthermore, individual differences in cognitive ability were reflected in the astronomy inquiry activities. While students, who received high scores, exhibited low levels of stress in the geology inquiry activities, they showed high levels of stress in the astronomy inquiry activities. It was concluded that, in the case of students with high scores in the study, the level of learning stress increased due to the raised anxiety in cognitive inquiry activities. In contrast, students, who received low scores in the study, exhibited high levels of stress in the geology inquiry activities, and low levels of stress in the astronomy inquiry activities.

• 한국항공우주학회지
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• 제45권10호
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• pp.898-906
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• 2017

본 논문은 우주선의 우주궤도 상에서 받는 외부 열원을 효과적이고 정확하게 계산할 수 있는 방법에 대해 논한다. 우주 외부 열원은 크게 태양직사광, 지구반사광, 지구복사열 세가지로 구분할 수 있다. 본 논문은 지구반사광과 지구복사열이 확산반사 및 방사를 따른다고 가정하고 지구표면을 다수의 구역들로 분할하여 이들과 인공위성 표면과의 반사/복사열을 계산하여 합산하였다. 본 연구에는 이들의 엄밀 적분식을 적용하여 수렴성을 극대화하였으며 많은 경우 정확한 결과를 가져올 수 있음을 알 수 있다. 그리고 외부 열원과 위성 표면 사이의 광선 차폐를 판단하기 위해 KD Tree Ray Tracing을 적용한 인공위성 궤도 열하중 계산 알고리즘을 개발하였다.

• KIEAE Journal
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• 제12권1호
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• pp.99-104
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• 2012

In event of selecting construction materials, taking ones found easily around make embodied energy saved. The earth construction could be an eco-friendly engineering from a views of keeping the embodied energy. The pour earth method construction, as one of earth constructions, improves liquidity of earth-mixed properties to build walls or foundations. This study is aimed at evaluating possibilities as to machinery constructions using pumping cars or excavators to be applied on natural non-dried earth which are purchased from sites neighboring to subject building. The study showed that the pumping car used construction was smoothly carried out without any remarkable difficulties and further, a compressed strength was found to keep a certain degree to possibly construct low-story buildings. However, it showed some different levels as to a compressed strength by locations of buildings. In the construction course, we couldn't use remicon plants or a remicon due to field conditions and we are forced to take excavators in compounding or mixing works. But, it is evaluated that actually liquidity or compressed strength will be better than in case of using machineries like remicon plants. These results make us determine that the wall construction using machineries is possible.

• 한국지반공학회논문집
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• 제21권8호
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• pp.55-61
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• 2005

현재 옹벽의 배면 동적토압을 산정할 때 주로 등가정적해석법인 Mononobe-Okabe 식이 이용되고 있다. 하지만 이식은 벽체와 뒤채움 지반간의 동적상호작용을 고려하지 못한다는 단점이 있다. 본 연구에서는 벽체와 뒤채움 지반간의 동적상호작용을 분석하기 위하여 건조 사질토로 뒤채움한 옹벽에 대하여 진동대 시험을 수행하였다. 벽체 단위중량, 입력가속도의 진폭 그리고 벽체 바닥면 거칠기를 변화시키면서 이들 각 인자가 동적토압에 미치는 영향을 분석하였다. 그 결과 벽체의 활동속도가 작은 경우에는 동적토압과 관성력간은 180도 위상차를 가졌지만 활동속도가 큰 경우에는 동적토압에 관성력과 동일한 위상을 가지는 작은 정점이 발생하였다. 동적토압의 크기는 벽체가속도와 벽체단위중량의 크기에 비례하였다. 또한 Mononobe-Okabe 방법으로 계산된 동적토압은 측정된 동적토압의 상한값으로 나타났다.

• KIEAE Journal
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• 제10권5호
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• pp.115-121
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• 2010

Lime was the solidifier mostly used at the fields of construction and civil works in the past. however, the development of Portland cement remarkably reduced the use of it. Recently as the concernment on circumstances gets higher, lime wined attention again as an eco-friendly material and was used at earth-using construction. This study examined the physical and chemical capacity of lime complexes with lime capacity improved, and performed fundamental study on the way to concretize by mixing it with earth. As a result, lime complex pressure strength was lower than cement pressure strength but it showed the possibility that its strength was improved by W/B control. The measurement of XRD after paste formation confirmed a compound generated by the reaction of Ca2+ion and Si, Al, and Fe from pozzolan reaction. A earth wall experiment by using lime complexes and earth showed that the higher, WB or the lower the quantity of unit combined materials, the lower the pressure strength was. The maximum pressure strength was maximum 11MPa when the quantity of unit combined materials was 450. It is because the composed earth particles had a high content of micro powder less than silt, so a lot of combination are demanded to secure fluidity. As a result of peptization experiment, after hardening, the material was not dissolved, which informed of the possibility of use as an outer subsidiary material. If the material is hardened by mold formation method, natural hardening crack appears. Cast expresses smart surface quality and enables to design for multiple purpose. The result shows the possibility of construction of low-story structures by using earth wall made of lime complexes and earth.

• 한국지구과학회지
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• 제25권2호
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• pp.115-115
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• 2004